I am confused about this site. Please provide a video and explain more.
This page explains how to build an application that will programmatically upload video to Twitch using v5 of the Twitch API.
If you are looking to upload video using the twitch.tv website, you can do so from the video producer (https://dashboard.twitch.tv/content/video-producer), click the purple "Upload" button in the top right. Note that you need to be an Affiliate or Partner to upload video. You can find more information about video on demand here: https://help.twitch.tv/s/article/video-on-demand.